When pain occurs in the left kidney, it may be from an infection or one of several underlying conditions.
The kidneys are a pair of organs in the abdomen on both the left and right sides of the body. The kidneys help process waste, which then leaves the body in the urine.
In this article, we look at the potential causes of left kidney pain, along with other symptoms and treatment options.
Not drinking enough water can cause kidney pain. If a person is dehydrated, waste can build up in the kidneys and cause a blockage.
Symptoms of severe dehydration can include:
- mood changes
- unclear thinking
The standard treatment for dehydration is to drink more fluid. In severe cases, a person may need intravenous fluids in order to rehydrate.
If bacteria get into the left kidney, they can cause an infection. Bacteria can enter the kidney from the urinary tract. In particular, an untreated urinary tract infection (UTI) can travel into the left kidney.
Some common symptoms of left kidney pain due to an infection include:
- dull ache
- sharp pain
- bad smelling or cloudy urine
- burning or pain during urination
- blood or pus in urine
- chills or fever
- pain in back or groin area
A person should seek medical advice if they have any of the above symptoms.
In most cases, a doctor will take a urine sample to test what type of infection a person has.
Doctors usually treat kidney infections with antibiotics. In more severe cases, a person may need to go to the hospital to receive intravenous antibiotics and fluids.
Kidney stones occur when salts and minerals build up in the kidneys and form small deposits. These stones can get bigger with time.
Smaller kidney stones usually pass from the kidneys and do not cause symptoms.
Larger kidney stones can cause discomfort when they move through the urinary tract from the kidneys to the bladder and can also get stuck in the kidney. They can cause symptoms such as:
- blood in the urine
- pain during urination
- sharp pain in the back or abdomen
The usual treatment for kidney stones involves drinking fluids to pass the stone and taking over-the-counter (OTC) pain medication.
For larger kidney stones, a doctor may recommend one of the following treatments:
- Shock wave lithotripsy: Shock waves break up the kidney stones.
- Ureteroscopy: A tool called a ureteroscope allows a doctor to see kidney stones and sometimes remove small ones as they retrieve the scope from the body.
- Medications: Specific medications help dissolve the stone.
Benign, or noncancerous, cysts are fluid-filled sacs. They can form in one or both kidneys and do not usually cause symptoms.
If a cyst gets too big, bursts, or becomes infected, it can cause kidney pain and symptoms, including:
- dull pain in the upper abdomen, side or back
- tenderness or sharp pain
Small cysts do not usually require treatment. If treatment is necessary, the options include:
- Sclerotherapy: A doctor uses a long needle to drain the cyst before applying alcohol to the cyst to harden it.
- Laparoscopy: A surgeon removes the cyst using a tool called a laparoscope.
Polycystic kidney disease (PKD) is a genetic condition that causes several cysts to form in one or both kidneys. PKD can alter the shape of the kidneys and can lead to kidney failure or other issues.
- high blood pressure
- blood in urine
- pain in one or both kidneys
- kidney stones
A person may not notice symptoms until the PKD cysts are large.
Treatment for PKD typically involves taking medication to slow kidney damage that high blood pressure causes.
- quitting or not taking up smoke
- exercising or doing physical activities for at least 30 minutes a day
- getting between 7 and 8 hours of sleep each night
- eating a healthful, balanced diet
- reducing stress
- losing weight if overweight or maintaining a healthy weight
Glomerulonephritis is a group of diseases that can cause kidney inflammation and damage the glomeruli, which filters blood.
If damage occurs to the kidneys, they work less effectively and can eventually lead to kidney failure.
There are two types of glomerulonephritis: acute and chronic.
Acute glomerulonephritis occurs suddenly and can accompany infections, such as strep throat. Symptoms include:
- blood in urine
- puffy face in the morning
- less frequent urination
Chronic glomerulonephritis develops slowly and may be the result of changes in the immune system or unknown causes. Symptoms include:
- high blood pressure
- blood in urine
- frequent urination at night
- swelling in ankles or face
- bubbly or foamy urine
Acute glomerulonephritis may clear up on its own. If it does not, a doctor may recommend medications to help weaken the immune system. They may also recommend draining the kidneys of extra fluid.
For chronic glomerulonephritis, treatment options include:
- keeping blood pressure under control
- taking calcium pills
- using diuretics
- avoiding eating extra protein, potassium, and salt
Hydronephrosis is a condition that causes a buildup of urine in the kidneys. It happens when an obstruction in the urinary tract prevents urine from fully draining from the kidneys.
Hydronephrosis is often the result of an infection or blockage, such as a kidney stone.
The condition may or may not cause symptoms. The main symptom is pain, which may be in the side of the back or the groin.
Other symptoms include:
- inability to fully drain the bladder
- increased urge to urinate
In most cases, a doctor must treat a person’s underlying condition first so the kidneys can drain.
In some cases, a doctor may need to remove the excessive urine.
Atherosclerotic renal artery stenosis (RAS) is when fatty deposits block or restrict blood vessels that lead to the kidneys. If a person does not receive treatment, the condition can cause damage to the kidneys, brain, and heart.
Symptoms of RAS include:
- sudden development of high blood pressure, particularly after 55 years of age
- unresponsive blood pressure when three or more medications do not help
- kidney failure due to an unknown cause
- sudden kidney failure following first use of an angiotensin converting enzyme (ACE) inhibitor
- quick buildup of liquid in the lungs
- more waste, or urea, from the liver in the blood
The treatment for RAS may involve a combination of lifestyle changes and medication to address a person’s overall cardiovascular health.
A person should see a doctor if they have frequent or intense pain on their left side.
They should also consult a doctor if other symptoms accompany the pain, such as fever or dizziness. Such symptoms can be a sign of an underlying health condition that needs addressing.
A doctor will ask several questions about the symptoms, when they occur, and severity of the pain. They will also perform a physical examination to assess both a person’s general health and the level of pain or tenderness in the back.
A doctor may also order several tests or imaging tests to determine the cause of the left kidney pain, including:
Left kidney pain can occur for a variety of reasons. People must talk to a doctor if they experience frequent or sharp pain or if they have other additional symptoms.
A doctor can help determine the underlying cause of left kidney pain and provide specific treatment.